Black Mint is a great plant to rid pests. Its a tall African marigold of some sort. Fairdinkumseeds in Australia sells these seeds. There are so many different oil, soap, plant, and other sources that make good deterants or insecticides. Tobacco is useful but be careful!

I place these together in a glass jar in the sun and let it sit for a few weeks. When I deem its strong enough and ready I put it in a spray bottle.

I've yet to encounter any pests that stand up to it. Keep in mind if its raining you will have to reapply the spray. There is peace of mind knowing none of the ingredients are damaging to humans or pets, and they are all easy to come by.

*One thing to note is that there are some plants that intensely dislike those plants of the Allium family to which Garlic belongs. I have never tried this natural pesticide on any of those plants so I cannot tell you how they would react. Any Legumes (beans, peas, lima beans, etc) and Asparagus dislike Alliums in their vicinity a great deal. I can only surmise that spraying the juices directly on them might have awful effect on their growth.

You could, of course, replace the Garlic with any other intensely aromatic herbs that repel insects and try that.